Pneumatic annunciator system

ABSTRACT

As a representative embodiment of the present invention, pressure-responsive indicators are coupled to suitable transducers monitoring selected operating conditions of an industrial machine. Pneumatic controls are arranged for providing first pneumatic signals when these operating conditions reach a predetermined value and producing second pneumatic signals should any of the operating conditions vary from its selected range. Other pneumatic controls are uniquely arranged for responding to the second signals to produce a brief third pneumatic signal which is effective to operate only the associated indicator while the other unaffected indicators are positively retained in their safe indicating positions. The indicators of the present invention are adapted to be stacked together and respectively include a number of passages adapted to coincide with the matching passages in the other indicators. One set of these passages in each indicator can be isolated from the other set by orienting the indicator in one position in relation to the other indicators. A second set of these passages is coupled to an alternately-positionable spool in each indicator which is uniquely arranged to select which of the passages in this other set is to be coupled to the pressure-responsive element in that indicator.

United States Patent Hurrah PNEUMATIC ANNUNCIATOR SYSTEM Robert S.Hurrah, 4108 Dupont, Houston, Tex. 77021 [22] Filed: July2l,l970

[21] Appl.No.: 56,892

[72] Inventor:

3,318,328 5/1967 Shrader 137/557 3,390,697 7/1968 Schmitz ..137/5572,888,023 5/1959 Eggenberger ..415/14 Primary Examiner-Edgar W.Geoghegan Assistant Examiner-Allen M. Ostrager Attorney-Donald Guim 1Mar. 28, 1972 [57] ABSTRACT As a representative embodiment of thepresent invention, pressure-responsive indicators are coupled tosuitable transducers monitoring selected operating conditions of anindustrial machine. Pneumatic controls are arranged for providing firstpneumatic signals when these operating conditions reach a predeterminedvalue and producing second pneumatic signals should any of the operatingconditions vary from its selected range. Other pneumatic controls areuniquely arranged for responding to the second signals to produce abrief third pneumatic signal which is effective to operate only theassociated indicator while the other unaffected indicators arepositively retained in their safe indicating positions. The in dicatorsof the present invention are adapted to be stacked together andrespectively include a number of passages adapted to coincide with thematching passages in the other indicators. One set of these passages ineach indicator can be isolated from the other set by orienting theindicator in one position in relation to the other indicators. A secondset of these passages is coupled to an altemately-positionable spool ineach indicator which is uniquely arranged to select which of thepassages in this other set is to be coupled to the pressureresponsiveelement in that indicator.

39 Claims, 15 Drawing Figures l 3, i i- PATENTEDMARES 1972 3651.643

SHEET 3 BF 6 3 4 1 FIG. IE i Robert S. Hurrah INVENTOR 89'' i ZM ATTORNE Y INVENTOR ATTORNEY PATENTEB MAR 2 8 I972 SHEET 6 BF 6 FIG. 5

BY jnm/ PNEUMATIC ANNUNCIATOR SYSTEM Various pneumatic systems have, ofcourse, been proposed heretofore for controlling the operation ofunattended industrial machines such as compressors, engines, or thelike. In

general, these systems typically include a plurality of electropneumatic controls any one of which, upon sensing an unsafe orundesirable operating condition of the machine being monitored, willquickly halt the machine as well as provide a visible signal showingwhich of these several operating condi tions caused the shutdown. Toaccomplish this, each of these selected operating conditions ismonitored by an appropriate condition-responsive monitor or transducerwhich is adapted to open a normally closed venting valve whenever thatoperating condition departs from a predetermined set point or operatingrange. Each venting valve is, in turn, connected by a normally pressuredconduit or tubing line to a pressureresponsive indicator relay whichtypically includes a movable member or so-called flag" operativelyarranged to present a first visual safe signal so long as the ventingvalve remains closed. An unsafe condition will, however, open theassociated venting valve so that, once the pressure is reduced in thetubing line, the flag will move to present a second visual signal thatthis particular condition is no longer correct or safe. Typically, theseindicator relays will also actuate a pneumatic control which halts themachine upon tripping of any one or more of the several relays.

Those skilled in the art will, of course, appreciate that the variousindicator relays employed heretofore typically rely upon unbalancedpressure forces acting on a movable piston or diaphragm element tomaintain the flags in their normal or safe" operating positions as wellas to shift the flags to their other positions for signaling amalfunction and actuating the shutdown controls. Generally speaking,these indicator relays employ one or the other of two basic techniquesfor controlling the position of the movable pressure-responsive member.In one common type of these indicator relays, the pressure-responsiveelement has equal pressure areas on each side of it. Thus, with thisstyle, so long as the associated transducer-operated venting valve isclosed, the visual indicator is maintained in its safe" position byimposing the full supply pressure on one side of the pressure-responsiveelement and a lesser pressure on the opposite side. Then, when an alarmcondition is sensed by the transducer and the control line is vented,the supply pressure is removed from one side of the pressure-responsiveelement and the lesser pressure, acting on the opposite side, causes theflag to signal the unsafe condition.

On the other hand, with the alternate style of these conventionalindicator relays, the pressure-responsive element has unequal effectiveareas on its opposite sides. Normally, the supply pressure is imposed onboth sides of the element; and opening of the venting valve will thenfunction to vent the supply pressure from the larger side of thepressure-responsive element, allowing the supply pressure on the smallerside to shift the flag to its alternate position.

Regardless of which of these two styles are utilized in amultiple-control annunciator system, those skilled in the art willappreciate that although these indicator relays of the prior art willusually halt the monitored machine, it is not at all uncommon for thevisual indicator or flag to fail to signal the origin of the malfunctionresponsible for the shutdown. This will, of course, require extensiveand needless trouble-shooting just to determine the underlying cause forthe shutdown of the machine. For example, in the typical annunciatorsystems employed heretofore, many of these prior indicator relaysinclude one or more valves for controlling the pneumatic pressuresinvolved in the shutdown system. As a result, should a venting valvewhich is opened by an improper operating condition be at the end of aparticularly long tubing line, there will be a significant lapse of timebetween the opening of this transducer-operated valve and the completeventing of the system. Accordingly, as the pressure begins to slowlydrop in the control line, the system shutdown valves will function andvent the pneumatic supply before the control line has vented. Shouldthis occur, the pressure still remaining in the long control line willunwittingly reset the indicator relay to again display a safe signal andthereby remove any indication as to which operating condition caused theshutdown of the machine.

To avoid this undesirable resetting of the indicator relays, variousarrangements have been typically employed heretofore for retarding theventing of the supply lines so that the longer control lines willhopefully be vented before the supply pressure is significantlydiminished. This, however, requires that the entire pneumatic system bepainstakingly balanced to prevent the loss of indication. Thisbalancing" must be done judiciously, however, or another equallyundesirable result will be introduced. If the supply to the indicatorsis maintained for too long a time after the initial sensor has vented,then an indicator relay monitoring a condition dependent upon thecontinued operation or movement of the machine will trip without validreason as the machine begins slowing and before the supply pressure hasbeen removed from the system. As a result, when the machine finallycomes to a halt, although the properly tripped indicator will correctlysignal that its associated condition was unsafe, the incorrectly trippedindicators will also falsely signal other unsafe conditions. This toois, of course, not at all desirable.

Accordingly, it is an object of the present invention to provide variousnew and improved pneumatic annunciator systems for reliably indicatingonly those malfunctioning operating conditions actually causing theshutdown of the machine being monitored without also falsely actuatingother indicators monitoring different and unaffected operatingconditions.

It is a further object of the present invention to provide new andimproved pneumatic indicators which are especially adapted for use withthe new and improved pneumatic annunciator systems of the presentinvention.

It is still another object of the present invention to provide new andimproved pneumatic indicators which are uniquely arranged for compactmounting on control panels with only a minimum of piping connectionsbeing required to adapt the indicators in a given group for respectivelymonitoring selected conditions.

These and other objects of the present invention are attained byarranging a new and improved pneumatic annunciator system havingpressure-responsive indicator means operatively coupled to transducermeans adapted for monitoring one or more operating conditions of anindustrial machine. To enable the system, first means are operativelycoupled to the transducer means and adapted for providing firstpneumatic signals in response to these operating conditions reaching apredetermined safe or desirable value. Second means are coupled to thetransducer means and operatively arranged for providing second pneumaticsignals in response to these operating conditions varying from thesevalues. Means responsive to such second pneumatic signals areoperatively arranged for imposing a brief, but positive, third pneumaticsignal of limited duration for actuating only the indicator meansmonitoring the unsafe or undesirable operating conditions to provide avisual indication of a malfunction while the first signals reliablyretain the other indicator means in positions indicating those operatingconditions which are still within safe operating limits.

The indicators of the present invention are uniquely arranged forcooperative grouping with one or more like indicators. To accomplishthis, each indicator has a body in which a pressure-indicator isarranged for movement between first and second indicating positions. Aplurality of passages are uniquely arranged in each body so that whentwo or more indicators are stacked together, the passages willrespectively be in communication with one another. By varying theorientation of the bodies in relation to one another as well as by meansof a reversible spool member uniquely arranged in each body, any one ofthese several passages can be selectively coupled to thepressure-responsive indicator in a given body and the other passagesisolated from the indicator.

The novel features of the present invention are set forth withparticularity in the appended claims. The invention, together withfurther objects and advantages thereof, may be best understood by way ofthe following description of exemplary apparatus employing theprinciples of the invention as illustrated in the accompanying drawings,in which:

FIGS. lA-lE schematically depict the sequential operations of apneumatic system arranged in accordance with the principles of thepresent invention and including a first set of controls adapted formonitoring one or more similarly characterized operating conditions of atypical internal combustion engine;

FIGS. 2A-2D schematically illustrate the sequential operations of asecond set of controls for the pneumatic system shown in FIGS. lA-lEwhile monitoring one or more of a second type of functionally relatedoperating conditions;

FIG. 3 schematically depicts an alternative control system for use witha group of controls such as shown in FIGS. 2A-2D;

FIGS. 4A-4C depict the sequential operations of a third set of controlsfor use with the pneumatic system shown in FIGS. lA-lE when a third typeof one or more operating conditions are to be monitored;

FIGS. 5 and 6 are cross-sectional views of a preferred pneumaticindicator relay for use with the several systems of the presentinvention.

Turning now to FIGS. lA-lE, a preferred embodiment is depicted of apneumatic annunciator system 10 arranged in accordance with the presentinvention, with the various elements thereof being shown in a schematicform for illustrating their various cooperative functions during atypical operating cycle. As best seen in FIGS. 1A, the new and improvedannun ciator system 10 is basically comprised of a first group 11 ofcontrols for selecting the operational modes of the system, a secondgroup 12 of system-initiating controls, one or more system-controlledelements as at 13, and a third group 14 of controls adapted forinitially resetting the various indicator relays employed with thesystem upon starting of the machine 15 being monitored as well as foractuating only those indicator relays sensing an unsafe condition. Tosimplify the explanation of the system 10, only a first set ofcondition-responsive indicator relays, as at 16 and 17, are depicted inFIGS. IAJE. It will be understood, however, that one or more indicatorrelays can be included with the system 10 either with or without therelays l6 and 17 for monitoring various types of conditions related tothe operation of the machine 15 for which the relays 16 and 17 are notsuited.

The first group 11 of controls are preferably comprised ofa pair ofsimilar or identical manually actuated valves 18 and 19 respectivelyhaving a first normally open position and a second position which, uponactuation of that valve, will close its inlet port and open its outletport. An appropriate threeposition manual actuator or selector, as at20, is operatively arranged between the valves 18 and 19 for alternatelyclosing the valves in the two extreme positions of the actuator andopening both of the valves when the actuator is in its depicted neutralposition. Accordingly, as seen in FIG. 1A, with the mode selector 20 inits neutral or run position, the valves 18 and 19 are in their normallyopen positions. Movement of the actuator 20 to its so-called testposition will move the valve 19 to its'alternate position but leave themain control valve 18 in its normally open position. Conversely,movement of the actuator 20 to its stop" position will shift the maincontrol valve 18 to its venting position without moving the valve 19from its normally open position.

A suitable pressure source, such as a typical supply 21 ofinstrument-quality air, is coupled by a conduit 22 to the inlet port ofthe main control valve 18, with the common or outlet port of this valvebeing connected to a supply manifold 23 having four branch conduits24-27 leading to the second and third groups 12 and 14 of the systemcontrols. Two of these manifold conduits 24 and 26 are respectivelycoupled to the inlets of similar or identical normally closedpressure-actuated three-way valves 28 and 29 adapted to vent theiroutlet ports so long as these valves are not actuated. On the otherhand, the other two manifold conduits 25 and 27 are respectively coupledto the inlets of similar or identical normally open pressure-actuatedthree-way valves 30 and 31 which, upon their actuation, are adapted tovent their outlet ports.

The outlet port of the normally closed valve 28 is coupled by a conduit32 to the pressure-responsive actuator 33 of the system-controlledelement 13 which, if the machine 15 is an internal combustion engine,might be a valve controlling the flow of fuel through a conduit 34 tothe machine. Accordingly, as is typical in such situations, thesystem-controlled element 13 is a normally closed three-way valveadapted to normally vent the fuel line 34 of the engine 15 and to admitfuel thereto from a suitable source 35 only so long as air of apredetermined pressure is supplied to the pressure-responsive actuator33.

For reasons that will subsequently be described, a branch conduit 36 iscoupled between the outlet port of the normally closed valve 28 in thesecond group 12 of system controls to that port of the manually actuatedvalve 19 which is normally closed and is opened upon operation of thevalve by movement of the manual mode-selector 20 to its test" position.A conduit 37 is coupled between the pressure-responsive actuator 38 ofthe normally closed control valve 28 and the outlet port of the manuallyactuated valve 19; and another conduit 39 is coupled between the inletport of the manual valve and the outlet port of the other normallyclosed valve 29 in the second group 12 of system controls. It will beappreciated, therefore, that so long as the valve 19 is in its depictedposition, opening and closing of the control valve 28 is selectivelyaccomplished by correspondingly opening and closing the control valve29. Similarly, the opening and closing of the system-controlled element13 is also solely dependent upon the control valve 29.

The outlet of the normally open valve 30 of the second group 12 of thesystem controls is coupled by a conduit 40 and an orifice 41 to oneinlet port of a two-way check valve assembly 42 having its other inletport connected by another orifice 43 to the conduit 32. The commonoutlet of the check valve assembly 42 is coupled by one conduit 44 tothe pressure-responsive actuator 45 of the normally closed valve 29 andby another conduit 46 to a first manifold 47 having one or more branchconduits, as at 48 and 49, which are respectively coupled to each of theseveral indicator relays l6 and 17. It will be appreciated, therefore,that by virtue of the orifice 41, the control valve 29 will remainclosed until this orifice has passed a sufficient volume of air to thepressure-responsive actuator 45 for the pressure applied thereto to openthis control valve. Thus, the delay provided by the orifice 41 willcorrespondingly delay the opening of the control valve 28 and theoperation of the system-controlled element 13.

The pressure-responsive actuator 50 of the normally open valve 30 iscoupled to the inlet of that valve by means of a selectively sizedorifice, such as a manually adjustable needle valve 51, in parallel witha one-way check valve 52 which blocks flow to the pressure-responsiveactuator but is adapted to readily open for venting the actuator and apressure accumulator 53 coupled thereto. It will be recognized,therefore, that admission of compressed air to the pressure-responsiveactuator 50 is selectively regulated by the orifice or needle valve 51.Moreover, by virtue of the accumulator 53, the pressure imposed on thepressure-responsive actuator 50 will always be equal to the pressuremaintained in the accumulator. Accordingly, since the orifice 51regulates the rate at which compressed air is admitted to theaccumulator 53 and the volume of the accumulator in turn furtherdetermines the rate at which the pressure imposed on the actuator 50increases, the orifice and the accumulator cooperate to delay theclosing of the normally open valve 30 for a selected period of timeafter air is first supplied to the second group 12 of system controls.On the other hand, upon venting of the supply manifold 23, the checkvalve 52 will be effective for bypassing the orifice 51 to permit theaccumulator 53 to be quickly vented.

The pressure-responsive actuator 54 of the normally open valve 31 in thethird group 14 of system controls is coupled by a conduit 55 to theoutlet of the normally closed valve 29 in the second group 12 of systemcontrols. For reasons that will subsequently be explained, the outlet ofthe normally open valve 31 is serially coupled by a conduit 56 to theinlet of another pressure-actuated normally open valve 57. Thepressure-responsive actuator 58 of this valve 57 is coupled to theconduit 56 by a selectively sized orifice or needle valve 59 which isparalleled with a one-way check valve 60 adapted for venting theactuator upon reduction of pressure at the inlet of thepressure-actuated valve. The outlet of this normally open valve 57 iscoupled by a conduit 61 to a second manifold 62 having one or morebranch conduits, as at 63 and 64, which are respectively coupled to eachof the indicator relays 16 and 17. It will be appreciated, therefore,that this third group 14 of system controls is effective for supplying ashort burst or pulse of compressed air to the manifold 62 which isterminated by the closing of either of the two normally open valves 31and 57. The significance of this function of the third group 14 ofsystem controls will subsequently be explained.

As schematically illustrated in FIG. 1A, the first set of the indicatorrelays 16 and 17 include new and improved indicator units 65 and 66respectively having separate bodies 67 and 68 with enclosed chambers 69and 70 arranged therein in which a piston, as at 71 and 72, is slidablymounted for selective movement back and forth. A suitable visualindicator or flag, as at 73 and 74, is coupled to each of the pistons 71and 72 as by a suitable connecting rod, such as at 75 and 76, andoperatively arranged so that, upon movement of its associated pistonfrom a retracted position to an extended position, a visual display willbe provided to warn that a malfunction has occurred. As depicted, thesecond inlet conduits 63 and 64 are respectively communicated with therear of the piston chambers 69 and 70; and the first inlet conduits 48and 49 are respectively communicated to the forward portion of thepiston chambers by conduits 77 and 78 in series with forwardly openingcheck valves 79 and 80. The significance of this arrangement willsubsequently be explained.

As is typical, the indicator relays 16 and 17 further include normallyclosed, condition-responsive valves, as at 81 and 82, that arerespectively coupled by conduits 83 and 84 to the forward portions ofthe chambers 69 and 70 of the indicator devices 65 and 66. To actuatethese valves 81 and 82, each is associated with a suitablecondition-sensing actuator, as at 85 and 86, that is operativelyarranged to maintain its associated venting valve closed so long as theparticular condition being monitored thereby is within a desiredoperating range. Thus, upon a change of the particular condition beingmonitored to what is considered to be an unsafe or undesirable status,the condition-sensing actuator 85 (or 86) will respond and open itsrespectively associated venting valve 81 (or 82).

As one example of the utility of the new and improved annunciator systemof the present invention, it will be assumed that the indicator relaysl6 and 17 are respectively monitoring different parameters functionallyrelated to the operation of the machine and which should not exceed apredetermined limit or range of conditions, but which can safely beeither within or below the operating range. For example, where themachine 15 being monitored by the annunciator system 10 is an internalcombustion engine or the like, such operating conditions might typicallybe the engine speed, cylinder-head temperatures, or cooling jackettemperatures. It will, therefore, be appreciated that to monitorconditions such as these, the condition-sensing actuators 85 and 86 arechosen for normally maintaining their respective valves 81 and 82closed; and that these valves will be opened only in the event thatsustained improper operation of the engine 15 causes any one or more ofthese various monitored conditions to exceed a safe limit.

To illustrate a typical application of the system 10, assume that themanual selector 20 has just been moved from its stop position to therun" position as depicted in FIG. 1A for initiating the operation of theannunciator system and, as a result, starting the engine 15 beingcontrolled thereby. Accordingly, movement of the selector 20 to the runposition will open the main control valve 18 for admitting compressedair from the pressure source 21 to the inlet manifold 23. The othermanual valve 19 will remain in the illustrated position. Since thecontrol valves 28 and 29 in the second group of system controls are atthis moment closed, compressed air will initially flow through only theconduits 25 and 27 respectively leading to the second and third groups12 and 14 of system controls.

Accordingly, once compressed air is admitted to the inlet manifold 23,the air will be simultaneously admitted by way of the normally openvalves 30, 31 and 57 to the conduits 40 and 61. However, even though thecondition-responsive valves 81 and 82 are closed at this time, the rateat which air is admitted to the first inlet conduits 48 and49 of theindicator relays 16 and 17 will be selectively regulated by the orifice41. Thus, for a finite period of time, the pressure imposed in theforward portions of the piston chambers 69 and 70 will slowly increasefrom atmospheric pressure to the operating pressure of the air source21.

On the other hand, since the serially arranged control valves 31 and 57in the third group 14 of system controls are both open at the timedepicted in FIG. 1A and there is no undue flow restriction between theinlet manifold 23 and the second inlet conduits 63 and 64 of theindicator-relays 16 and 17, the full operating pressure of the airsource 21 will be quickly imposed in the rearward portions of the pistonchambers 69 and 70. Accordingly, since the pressure differential will bequickly developed across the two pistons 71 and 72, the third group 14of system controls will function to temporarily shift the visualindicator flags 73 and 74 forwardly to their extended positions asillustrated in FIG. 1A. It will be noted that at this point the secondgroup 12 of system controls are still maintaining the fuel valve 13closed to preclude the admission of fuel from the fuel supply 35 to theengine 15.

The compressed air passing through the conduit 56 interconnecting theserially arranged normally open valves 31 and 57 will, however,gradually impose an increased pressure on the pressure-responsiveactuator 58 of the latter valve at a selected rate determined by theorifice 59. Once a sufficient pressure is applied to the actuator 58,the normally open valve 57 will be closed and the compressed air in thesecond manifold 62 will be vented as depicted in FIG. 1B. Similarly,once a sufficient volume of compressed air has passed the orifree 41 tosignificantly increase the pressure in the conduit 46 and the firstmanifold 47, the normally closed valve 29 will be opened by the increaseof pressure on its actuator 45 and the pistons 71 and 72 will be shiftedrearwardly in their respective piston chambers 69 and 70. It will,therefore, be appreciated that the rearward movement of the pistons 71and 72 will be positively assured since the pressure in the forwardportions of the piston chambers 69 and 70 will be approaching that ofthe air source 21 and the pressure in the rearward portions of thechambers will be decreased to atmospheric pressure once the controlvalve 57 is closed.

It will also be noted in FIG. 18 that once the control valve 29 opens,the second group 12 of system controls functions to admit compressed airto the pressure-actuator 38 by way of the manual valve 19 tosuccessively open the control valve 28 and the automatic fuel valve 13.Although the engine 15 is now starting, the normally open valve 30 ofthe second group 12 of system controls is still open and will not closeuntil a sufficient quantity of air has passed the controllable orifice51 to raise the pressure in the accumulator 53 to the actuating pressureof the pressure-responsive actuator 50.

Particular note should be made that the valve 29 must open before thevalve 30 closes in order for the fuel valve 13 to be opened and allowthe engine 15 to start. Thus, should one of the transducer-actuatedvalves 81 and 82 be open by virtue of some malfunction, the valve 30will close before the valve 29 opens and the engine 15 cannot bestarted. This interaction between the valves 29 and 30 is, therefore,provided by the cooperative relation of the orifice 51 and accumulator53 which determines the delay between the opening of the valve 29 andthe closing of the valve 30 if no malfunction occurs. Thus, by virtue ofthis timed delay, a brief flow or pulse of compressed air is provided tothe first manifold 47 for a selected time interval which will ordinarilybe sufficient to allow the engine 15 to start but which, if either ofthe valves 81 or 82 are open, will prevent the engine from beingstarted. It will be realized, therefore, that the opening of the valve29 provides a signal which is indicative that the operating conditionsbeing monitored by the transducers 81 and 82 are each in a safeoperating range.

Once, however, the valve 29 opens and the valve 30 closes as shown inFIG. 1C, the double-acting check valve 42 will function as an enablingdevice to condition the annunciator system 10 for subsequentlyresponding to a malfunction in the engine which will cause an excessiveincrease in any of the one or more operating conditions being monitoredby the new and improved annunciator system of the present invention. Thevarious elements of the annunciator system 10 will, of course, remain intheir positions respectively illustrated in FIG. 1C so long as none ofthe operating conditions being monitored by the condition-responsivevalves 81 and 82 do not exceed a predetermined level and cause one ormore of these valves to open. Ordinarily, the various elements of thecontrol system 10 will remain as illustrated until the engine 15 is tobe halted routinely. To stop the engine 15, the manual selector issimply moved to its stop position which closes the main control valve 18to block further communication between the air source 21 and the inletmanifold 23 and simultaneously vent the entire system to atmosphere.

Turning now to FIG. 1D, the annunciator system 10 is depicted at themoment when the operating condition being monitored by one of thecondition-responsive valves, as for example the valve 82 controlling theindicator 66, has exceeded its predetermined limits. When this occurs,the condition-responsive valve 82 will open as illustrated and rapidlyvent the first manifold 47 and the conduit 44 coupled to thepressure-responsive actuator 45 of the valve 29 so as to rapidly closethis latter control valve. Closing of the valve 29 can, of course, beconsidered as producing a second signal for indicating that one of theoperating conditions being monitored has exceeded its selected range.

Reclosing of the control valve 29 will, therefore, simultaneously ventthe conduit 55 coupled to the actuator 54 and the conduits 37 and 39coupled to the actuator 38. Venting of the actuator 38 will, in turn,close the control valve 28 which vents the conduit 32 coupled to theactuator 33 so that the fuel valve 13 is immediately closed.Simultaneously therewith, the control valve 31 is reopened and, asillustrated in FIG. 1D, compressed air is again admitted to the secondmanifold 62 by way of the still-open control valve 57. As will beappreciated, therefore, with the forward portion of the piston chamber70 now being at atmospheric or certainly near-atmospheric pressure, thepiston 72 will be positively impelled forwardly to shift the visualindicator 74 to its forwardmost position to indicate that it is theoperating condition being monitored by the indicator relay 17 which wasresponsible for the shutdown of the engine 15.

It will be noted, however, by comparing FIG. 1D with FIG. 1E that thereapplication of pneumatic pressure in the conduit 56 occasioned by theopening of the valve 31 will soon close the control valve 57 downstreamthereof once the orifice 59 has permitted the pressure applied to thepressure-responsive actuator 58 to rise to a sufficient level to operatethe latter valve. Thus, the second manifold 62 will be exposed to only abrief surge of pressure upon opening of the valve 31, with this pressurebeing quickly discontinued upon closing of the valve 57. In other words,the third group 14 of system controls is operative for producing amomentary surge or pulse of compressed air which functions as a thirdsignal for shifting the piston 72 and the visual indicator 74 forwardly.The other piston 71 will, of course, also be subjected to this momentarypressure pulse or signal and may very likely tend to begin movingforwardly. Yet, since fully pressured air will still be trapped in theforward portion of the piston chamber 69 between the check valve 79 andthe still-closed conditionresponsive valve 81, even should the piston 71shift forwardly the trapped air will be further compressed so that thepiston will be positively returned and retained in its normal rearwardposition once the control valve 31 closes and the manifold 62 is ventedas shown in FIG. 1E. It will be recalled, of course, that the compressedair which is effective for retaining the piston 71 in position isprovided by the initial signal previously produced.

It will, of course, be appreciated that there are other typicaloperating conditions which must also be monitored but which areincapable of providing a meaningful control signal until after theengine 15 has been started. For example, with a typical internalcombustion engine, engine-driven oil pumps, water-circulation pumps, andthe like, are often employed. Although it is important to monitor thedischarge pressures of such pumps and guard against excessively lowpressures, these pumps cannot develop their expected operating pressuresuntil the engine 15 is either approaching or has just reached fulloperating speed. A typical pressure-sensing transducer monitoringconditions such as these will, therefore, falsely signal that amalfunction is occurring until the engine 15 has been started. Thus,since the indicator relays 16 and 17 depicted in FIG. 1A are criticallydependent upon their respective condition-responsive valves 81 and 82being closed before the engine 15 is started, an alternative arrangementof pneumatic controls must be provided for those indicator relays whichare to monitor those operating conditions which are not satisfied whenthe engine is first started but which will be satisfied once the engineis operating and is functioning properly.

Accordingly, as depicted in FIG. 2A, an alternative or additional set ofcontrols 87 is provided for use with one or more indicator relays, as at88 and 89, respectively including typical condition-responsive valvesand 91 which will initially be open and then subsequently close eitheras the engine 15 is starting or once the particular operating conditionswhich they are monitoring respectively reach a predetermined value orrange. It will be appreciated, of course, that the controls 87 are to beoperatively associated with the annunciator system 10 whether or not theindicator relays 16 and 17 are included. For example, if the indicatorrelays 16 and 17 are not employed with the additional set of controls87, the first and second inlet conduits 48, 49, 63 and 64 would not beneeded. On the other hand, if the indicator relays l6 and 17 are to beassociated with the second set of controls 87, the relays will functionin the same manner as previously described. The operation of theseadditional controls 87 will, therefore, not be affected by either theinclusion or the omission of the indicator relays 16 and 17 in theannunciator system 10.

As illustrated in FIG. 2A, the second set of indicator relays 88 and 89include pneumatic indicator devices, as at 92 and 93, operativelycontrolled by the condition-responsive valves 90 and 91 which have beenappropriately selected for monitoring this second group of operatingconditions. It will, of course, be noted that the second indicatordevices 92 and 93 are otherwise identical or similar to those previouslydescribed and their second inlets are coupled in the same manner tobranch conduits 94 and 95 of the second manifold 62. The first inlets ofthe indicator devices 92 and 93 are, however, coupled by branch conduits96 and 97 of a first manifold 98 connected to the outlet port of atwo-way check valve 99 that is similar or identical to the firstassembly 42 previously described. One inlet of the check valve assembly99 is connected by a conduit 100 to the outlet of a normally opencontrol valve 101 having its inlet connected to a branch conduit 102 ofthe first manifold 47. The other inlet of the check valve assembly 99 isconnected by way of a selected orifice 103 and a branch conduit 104 thatis coupled to the conduit 40 upstream of the delay orifice 41 (FIG. 1A).The pressure-responsive actuator 105 of the control valve 101 is coupledby a branch conduit 106 to the conduit 104.

It will be appreciated, therefore, that this additional set of controls87 will be immediately responsive to the controlled pulses of compressedair supplied to the second manifold 62 by the third group 14 of systemcontrols. On the other hand, as will subsequently be explained, unlessthe condition-responsive valves 90 and 91 are closed before thecessation of the timed pulse of compressed air supplied to the conduit104 by the second group 12 of system controls, the annunciator systemwill halt further operation of the machine 15.

Accordingly, the additional controls 87 are depicted in FIG. 2A at thesame point in time illustrated in FIG. 1A. The control valves 31 and 57in the third group 14 of system controls have just functioned aspreviously described for delivering the brief burst of compressed air tothe second manifold 62 to simultaneously move the first and secondvisual indicators 73, 74, 107 and 108 momentarily outwardly. It will benoted, however, that the pneumatic pressure in the conduit 104 isfunctioning to temporarily hold the control valve 101 closed so that thepressure in.the first manifold 47 can increase at its usual rate forretracting the first indicators 73 and 74 if, of course, the firstcondition-responsive valves 81 and 82 are closed. 0n the other hand, asshown in FIG. 2A, so long as either of the second condition-responsivevalves 90 and 91 remain open, the pressure in the other first manifold98 cannot increase to any significant level. The second visualindicators 107 and 108 will, of course, remain in their extendedpositions as depicted in FIG. 2A until the second conditionresponsivevalves 90 and 91 are closed. The initial open positions of the secondcondition-responsive valves 90 and 91 will, therefore, not prevent theinitial starting of the engine so long as the valve 101 remains closedfor isolating the first manifolds 47 and 98 from one another.

As previously defined, the additional controls 87 are operativelyarranged to permit the engine 15 to be started and continue operating ifthe several conditions being monitored by the second set of indicatorrelays 88 and 89 reach their respective operating ranges no later than ashort time after the engine has been started. It will be recalled thatpressure is immediately introduced to the conduit 104 when the engine 15is started (FIG. 1A) and that this pressure will be maintained onlyuntil the valve 30 is closed. Thus, as previously described, thisdesired timing function is accomplished by selectively arranging theorifice 51 and the accumulator 53 to close the valve 30 at the end of apredetermined time interval so that cessation of the pressure in theconduit 104 will provide a positive signal for enabling furtheroperation of the engine 15 only if the second set of operatingconditions have then reached a satisfactory level. This predeterminedtime interval is, of course, related to what should be the normal timerequired for these operating conditions to respectively reach a properlevel after the engine 15 starts.

Accordingly, as illustrated in FIG. 2B, if the conditionresponsivevalves 90 and 91 close while the second group 12 of system controls arestill supplying compressed air to the to the conduit 104, the orifice103 will enable the pressure in the first manifold 98 to rapidly buildup for retracting the second indicators 107 and 108 in the same manneras the first indicators 73 and 74. It will be appreciated, of course,that the orifice 103 will prevent excessive loss of compressed air fromthe conduits 40 and 104 so long as the condition-responsive valves 90and 91 are open and the second group 12 of system controls is supplyingthe timed flow of compressed air to these conduits.

On the other hand, should an operational malfunction hold either of thecondition-responsive valves 90 and 91 open longer than anticipated, oncethe valve 30 closes the pressure in the conduit 104 will be relieved toquickly open the valve 101 and couple the pressured first manifold 47 tothe stillvented first manifold 98. It will be appreciated, therefore,from the preceding description as well as from FIG. ID that venting ofthe pressured first manifold 47 will immediately initiate the shutdownof the engine 15. Thus, depending on the positions of thecondition-responsive valves and 91 at the end of this selected timeinterval governed by the second group 12 of system controls, the signalprovided thereby upon the resulting cessation of pneumatic pressure inthe conduit 104 will in one instance permit continued operation of theengine 15 and in the other instance immediately terminate the operationof the engine.

When the condition-responsive valves 90 and 91 are safely closed beforethe valve 30 closes to discontinue the signal in the conduit 104, thevisual indicators 107 and 108 will be retracted; and, once the valve 101opens as shown in FIG. 2C, the first manifolds 47 and 98 will be coupledto one another by way of the check valve assembly 99. The additionalcontrols 87 will, of course, remain in their depicted respectivepositions so long as the operating conditions being monitored by thesecond indicator relays 88 and 89 are within their specified limits.

It will, of course, be appreciated that opening of one or more of thefirst set of condition-responsive valves 81 and 82 as depicted in FIGS.1D and IE will initiate operation of the control system 10 to causeshutdown of the engine 15 in the same manner as already described. Whenthis occurs, so long as the second condition-responsive valves 90 and 91were closed, the visual indicators 107 and 108 will be retained in theirsafe positions. Similarly, opening of either of the second set ofcondition-responsive valves 90 and 91 will also cause the interconnectedmanifolds 47 and 98 to be vented to atmosphere as depicted in FIG. 2D.Venting of the first manifolds 47 and 98 will, therefore, immediatelycause shutdown of the engine 15 in the same manner as depicted in FIG.1E. Although it is not necessary to illustrate the actions of theadditional set of controls 87 when the annunciator system 10 isfunctioning as illustrated in FIG. IE, it should be noted that thevisual indicator 108 (as well as the indicators 73 and 74) will beretained in its safe" position and the momentary burst of compressed airsupplied by the third group 14 of system controls to the second manifold62 will move only the other visual indicator 107 forwardly to indicatethe source of the malfunction causing the shutdown of the engine 15.

The operating conditions which are to be monitored by the additional setof pneumatic controls 87 must, of course, all reach satisfactory levelswithin the time interval provided by the orifice 51 and the accumulator53 of the second group 12 of system controls. It will be appreciated,however, that there may be situations where one or more of suchoperating conditions may not necessarily reach a satisfactory level bythe time that the valve 30 closes.

Accordingly, to permit one or more of such different operatingconditions to be reliably monitored by the annunciator system 10, analternate group 109 of system controls is depicted in FIG. 3 which canbe employed for controlling a set of pneumatic controls 110 similar oridentical to those depicted in FIGS. 2A-2D and operatively arranged forcontrolling one or more indicator relays as at 111. Since the respectivefunctions of the alternate group 109 of system controls and the set ofcontrols 110 and 111 are identical to their respective counterpartspreviously described, it is necessary to point out only that theinterval before the cessation of the timed pulse of compressed airsupplied to the conduit 112 will be selected in accordance with theparticular condition being monitored. This time interval may, of course,be either longer or shorter than that provided by the second group 12 ofsystem controls. Thus, if the branch conduit 113 from the first manifold47 is not to be communicated with the first manifold 114 until somelater time, the controllable orifice 115 as well as the size of theaccumulator 116 can be appropriately selected for closing the valve 117as determined by the par ticular situation. More than one system ofcontrols, as at 109-111, can, of course, be included in the system 10.

In addition to the first and second types of conditions previouslydescribed with reference to FIGS. 1A-1E and FIGS. 2A-2D, a third type ofoperating condition is often experienced while operating typicalindustrial machines. These third conditions are those which may not besatisfied until some undetermined time after the machine is started butwhich will also be temporarily deficient as that machine is first beingstarted. For example, in a typical installation, there will be instanceswhere a low temperature, a low liquid level, or a low pressure willnormally be experienced until sometime after the machine being monitoredis started; but, once this condition is satisfied, a subsequentreduction will then endanger the machine. Thus, in distinction to thesecond type of conditions previously described, these third conditionsmay either remain unsatisfied for long periods of time or else they willbecome satisfied at some unpredictable time after the machine hasstarted.

Accordingly, a third set of pneumatic controls 118 is depicted in FIG.4A for monitoring such conditions. Hereagain, this third set of controls118 is to be used in conjunction with the control system irrespective ofwhether or not the indicators 16 and 17 are utilized. Similarly, thethird set of controls 118 is wholly independent of the second set ofcontrols 87 and can be used either with or without either this lattersystem or the pneumatic controls 109-1 1 1.

As illustrated in FIG. 4A, the second manifold 62 is also coupleddirectly to the second inlets of each of one or more indicator relays,as at 119 and 120, such as those previously described. A branch conduit121 (which will be either coupled to or paralleled with the branchconduit 104 if the second set of controls 87 is being used) is coupledto the conduit 40 between the delay orifice 41 and the control valve 30(FIG. 1A). It will, of course, be appreciated that the conduit 121 couldbe alternatively coupled to the conduit 112 (FIG. 3) if the timedinterval of the pulse developed by the group 109 of system controls wasto be employed. In any event, this branch conduit 121 is, in turn,divided into two other conduits 122 and 123 which are respectivelycoupled to the inlet of a twoway check valve 124 (similar or identicalto those previously described at 42 and 99) as well as to the inlet portofa typical pilot-operated check valve 125. The other inlet ofthetwo-way check valve 124 is coupled by a conduit 126 to the inlet of thecontrol valve 28 controlling the system-controlled element 13 (FIG. 1A).

The outlet of the two-way check valve 124 is coupled to the inlet of anormally closed control valve 127 having its pressure-responsiveactuator 128 coupled by a conduit 129 to the outlet port of thepilot-operated check valve 125. The outlet of the normally closedcontrol valve 127 is coupled by one conduit 130 to thepressure-responsive actuator 131 ofa normally open control valve 132 andby another conduit 133 and an orifice 134 to one inlet of anothertwo-way check valve 135. The other inlet of this latter check valveassembly 135 is coupled by a conduit 136 to the outlet of the normallyopen control valve 132; and the outlet of this check valve assembly iscoupled by a first manifold 137 having branch conduits 138 and 139 whichare respectively connected to the first inlets of the indicator-relays119 and 120. For reasons that will subsequently be explained, a conduit140 is coupled between the first manifold 137 and the reset or pilotport of the pilotoperated check valve 125. The inlet of the normallyopen valve 132 is coupled to a branch conduit 141 of the first manifold47.

Accordingly, the third set ofcontrols 118 is depicted in FIG. 4A as itwill appear at the same moments respectively illustrated in FIGS. 1A and2A. Since the second manifold 62 is coupled directly thereto, the briefpulse of compressed air applied thereto will also be effective forinitially moving the visual indicators 142 and 143 forwardly. Hereagain,as was the case with the second set of controls 87, since the thirdcondition-responsive valves 144 and 145 will not be closed for at leasta short time interval, the pressure in the first manifold 137 willremain at, or very near to, atmospheric pressure until such time thatall of the third condition-responsive valves have closed when theirrespective operating conditions have reached their selected operationalranges for the first time. Similarly, since the control valve 132 istemporarily closed, the pressure in the first manifold 47 of the firstset of indicator relays 16 and 17 can reach full pressure irrespectiveof what is happening in either the second or third sets of controls 87and 1 18.

Pressure will, however, be applied by way of the conduits 40, 121 and122 to the left-hand inlet of the two-way check valve 124 and to theinlet of the pilot-operated check valve to retain the control valve 127open and supply compressed air by way of the orifice 134 to the othertwo-way check valve 135. This same pneumatic pressure will also functionto maintain the control valve 132 closed. The various elements depictedin FIG. 4A will retain their same positions whenever the system 10 is atthe point illustrated in FIG. 18. Similarly, even after the system 10 isfunctioning as illustrated in FIG. 1C, should the thirdcondition-responsive valves 144 and still be open as shown in FIG. 4A,the various elements of the third set of controls 118 will remain in thesame positions. These intermediate situations are, therefore, notillustrated. It should be noted, however, that the pilotoperated checkvalve 125 will initially trap pressure in the conduit 129 to retain thevalve 127 open even after the conduit 123 is vented by closing of thevalve 30. In this manner, the pressure in the conduit 129 will then beeffective for temporarily retaining the valve 127 closed for anindeterminate period of time.

Once, however, the condition-responsive valves 144 and 145 are closed asseen in FIG. 4B, the pressure will rapidly increase in the firstmanifold 137 to shift the visual indicators 142 and 143 to their safepositions and simultaneously supply a reset signal or pressure pulse tothe pilot-operated check valve 125 by way of the conduit 140. It will beappreciated that once the reset signal is applied to the pilotoperatedcheck valve 125, it will open to vent the pressure trapped in theconduit 129 which closes the control valve 127. In this manner, thereset signal to the pilot-operated check valve 125 will be effective forventing the control actuator 131 which, in turn, opens the control valve132.

As previously described, the shutdown operations of the annunciatorsystem 10 as shown in FIG. 1A and the several sets of controls 87, 110and 118 are wholly independent of one another. Thus, opening of one orthe other of the first or second condition-responsive valves, as at 82and 90, will cause the annunciator system 10 to halt the engine 15without affecting the positions of the indicators 142 and 143.Conversely, as illustrated in FIG. 4C, upon opening of either of thecondition-responsive valves 144 and 145, the third set of controls 118will halt the engine 15 in the same manner as already described. Thus,as shown in FIG. 4C, should the conditionresponsive valve 145 be opened,venting of the first manifold 137 will simultaneously cause venting ofthe first manifold 47 as depicted in FIG. 1D. This, in turn, willproduce the momentary pulse of compressed air through the secondmanifold 62 to move the appropriate visual indicator 143 outwardly whilethe check valve 146 and the still-closed condition-responsive valve 144cooperate to retain the visual indicator 142 properly positioned. Oncethe first manifold 47 is vented, the annunciator system 10 will againfunction as previously described in FIGS. 1D and IE to shutdown theentire system and halt the engine 15.

Referring again to FIG. 1A, it will be appreciated that a test can bemade of the annunciator system 10 (as well as the second and third setsofcontrols 87, 110, 111 and 118) by momentarily positioning the manualselector 20 in its test" position. This will simply supply compressedair through the valve 19 from the conduit 32 (valve 28 initially beingopen) back to the actuator 38 to retain the valve 28 in its openposition so as to keep the fuel valve 13 open irrespective of thesubsequent closing of the valve 29 to test the system. Once the valve 19is in its test position, any of the condition-responsive valves, such as81, can be manually opened to simulate a malfunction condition. Thiswill cause the appropriate visual indicator, such as 73, to be extendedwithout closing the fuel valve 13. In this manner, a simulated test canbe made of the system 10 without halting the engine 15. It will benoted, however, that moving of the manual actuator 20 to the testposition will be ineffective until the valve 28 has been opened for thefirst time.

Turning now to FIGS. and 6, cross-sectional elevation and plan views areshown of a preferred embodiment of a new and improved pneumaticindicating device 150 especially adapted for use with the annunciatorsystem of the present invention and arranged in accordance with theprinciples of the present invention. The indicating device 150 isuniquely arranged for cooperative grouping with one or more similar oridentical devices, as at 151-153, which can be conveniently mounted as aunitary assemblage on a control panel (not shown) with a minimum numberof interconnections.

As best seen in FIG. 6, the new and improved indicating device 150includes a generally rectangular body 154 of uniform thickness andhaving opposed upper and lower planar faces to facilitate stacking ofthe device with the other devices 151-153 in the assemblage. A firstelongated bore formed lengthwise through about the middle of the body154 includes a short reduced forward portion 155 coincidentally alignedwith a longer enlarged-diameter rearward portion 156 in which alongitudinally movable piston member 157 is slidably disposed. Toprovide an indication of the relative positions of the movable pistonmember 157, a reduced diameter rod 158 coaxially mounted on the pistonand extended through the forward bore 155 is operatively coupled to asuitable visual indicator or flag 159.

Sealing members, such as O-rings 160 and 161, are respectively arrangedaround the piston 157 and the internal wall of the forward bore 155 fordefining a first pressure chamber in the enlarged bore 156 ahead of thepiston member. To provide communication with this first pressurechamber, a transverse passage 162 is extended across the body 154through the forward end of the enlarged bore 156 and preferablyterminated by threaded counterbores or ports 163 and 164 formed on therear face of the device. To close the rear of the enlarged bore 156, aclosure member 165 carrying a sealing member 166 is complementallyfitted into the rearward end of the bore and retained therein by a coverplate 167 mounted across the rear of the body 154 and secured thereto asby bolts 168 and 169. To provide communication with the second pressurechamber defined between the sealing members 160 and 166, a verticalpassage 170 is formed through the body 154 between its upper and lowerfaces to intersect the enlarged bore 156 just ahead ofthe closure member165.

A second elongated bore 171 is formed in the body 154 adjacent to oneside of the first elongate bore and intersects it through a smallercoincidentally aligned passage 172 that intersects the transversepassage 162 about midway between the port 163 and the enlarged bore 156.As best seen in FIG. 5, a first pair of vertical passages 173 and 174are formed through the body 154 between its upper and lower faces andintersect the second bore 171 at longitudinally spaced intervals.Similarly, a second pair of vertical passages 175 and 176 are formed inthe opposite side of the body 154 between its upper and lower faces. Forreasons that will subsequently be explained, it will be noted that thepassages 173-176 are symmetrically disposed on opposite sides of theenlarged bore 156 and are selectively positioned so that the lateralspacing between each of the four passages and the first bore is equaland the longitudinal spacing between the forward and rearward passagesof each pair is equal.

An elongated tubular spool 177 is disposed in the second bore 171 andcarries three longitudinally spaced sealing members or O-rings 178-180cooperatively arranged thereon for dividing the elongated bore intoforward and rearward enclosed spaces that are isolated from one anotherand are respectively intersected by the vertical passages 173 and 174.The longitudinal bore 181 through the spool 177 is terminated at itsopposite ends by semispherical counterbores 182 and 183 respectivelyformed in the forward and rearward end surfaces of the spool. Forreasons that will subsequently be explained, a single transverse passage184 is formed through the spool 177 between the O-rings 179 and 180 andintersects the longitudinal bore 181 through the spool. It will beappreciated from FIG. 5 that with the spool 177 in the positionillustrated and retained in the second bore 171 by the cover plate 167,the rearward enclosed space will be in communication with the verticalpassage 173 but will be isolated from the longitudinal bore 181 throughthe spool by the O-rings 178 and 179. Conversely, by virtue of thetransverse passage 184, the forward enclosed space between the O-rings179 and 180 will be in communication with the vertical passage 174 aswell as the longitudinal bore 181 through the spool 177.

With the spool 177 in this position, the vertical passage 173 and itsassociated rearward enclosed space will be isolated from thelongitudinal passage 172 and the transverse passage 162 but thelongitudinal bore 181 and the transverse passage 184 in the spool willcommunicate the vertical passage 174 with the passages 162 and 172 andthe enlarged bore 156. To permit flow from the vertical passage 174 tothe enlarged bore 156, a typical valve member, such as a ball 185, isoperatively disposed in the forward end of the second bore 171 andyieldably biased into seating engagement with the counterbore 183 in theforward end of the spool 177 by a spring 186 that is abutted against ashoulder 187 formed by the junction of the bore 171 and passage 172. Inthis manner, compressed air can readily flow between the verticalpassage 174 and the enlarged bore 156 but the spring-biased ball 185will prevent flow in the opposite direction.

It will be appreciated from FIG. 6 that the several indicating devices-153 are well suited for being stacked together to form a unitaryassemblage of any number of the devices. To facilitate their stacking,thin rectangular plates, as at 188-190, each having five holes thereincorresponding to the vertical passages and 173-176 and respectivelycarrying a sealing member, as at 191, are placed between the opposedfaces of each indicating device. To provide a convenient connection withthe vertical passages 170 and 173-176, generally rectangular bodies, asat 192 and 193, are mounted on the top and bottom of the stackedindicating devices 150-153 and provided with appropriate ports, as at194-196, for communicating with the passages 170 and 173-176. Thecomplete assemblage of indicating devices 150-153, the plates 188-190,and the upper and lower manifold blocks 192 and 193 are secured togetherby vertical bolts as at 197 and 198. As best described in a copendingapplication, Ser. No. 777,670, by the present inventor, optical membersor lenses, as at 199, are respectively arranged between the forward endsof the spacer plates, as at 188 and 189, for providing a positive visualindication only when the flag 159 is in its forward position immediatelyto the rear of the lens. To further assure that the flag 159 will remainin its warning position when urged forwardly by the pressure pulseproduced upon the occurrence of a malfunction, a spring-biased detent200 is arranged in the body 154 for cooperation with a reduced portion201 arranged on the rod 158.

Accordingly, it will be appreciated from the preceding description thatwhen the indicating device 150 is to be used in the annunciator system10, the first manifold (as at 47 in FIG. 1A) will be coupled to thevertical passage 174 and the second manifold (as at 62 in FIG. 1A) willbe coupled to the vertical passage 170. The port 163 can be plugged andthe port 164 coupled to the condition-responsive valve (as at 81 in FIG.1A). The vertical passages 173, and 176 will, of course, be ineffectivefor purposes of operating the indicator device 150.

As previously explained with reference to FIGS. lA-lC, the briefpressure pulse initially delivered by way of the manifold 62 to thevertical passage 170 will be effective for temporarily shifting thepiston 157 and its associated flag 159 forwardly. Then, once sufficientpressure has built up in the forward portion of the enlarged bore 156,the piston 157 will be returned to the position illustrated in FIG; 6 tobring the flag 159 to a position indicating a safe operating condition.As previously described with reference to FIGS. lD-lE, venting of thetransverse passage 162 will, of course, be effective for initiating themomentary pressure pulse which is delivered by way of the verticalpassage 170 to the rear of the piston 157 for driving the pistonforwardly. Similarly, if the transverse passage in the indicating device162 is not vented, the momentary pulse delivered to the vertical passage170 will not be effective for moving the piston 157 a sufficientdistance forwardly to indicate a malfunction.

It will be recognized, therefore, that by stacking the severalindicators 150-153 as shown in FIG. 6, their respective passages 170will be in alignment with one another to provide an uninterruptedpassage from top to bottom of the assemblage which will serve as thecommon second manifolds, as at 62, with a common port as at 194 and 196.On the other hand, by reversing the elongated spool 177, thelongitudinal bore 181 can be selectively placed in communication witheither of the vertical passages 173 and 174. The ball member 185 will,of course, be left in its depicted position for seating with either theseat 182 or 183. Moreover, by turning the body 154 over, the passages173 and 174 will then be placed into communication with the passages 175and 176 in the adjacent devices 151 and 152. Thus, by reversing thevalve spool 177, two additional combinations of interconnection can bereadily obtained.

It will be seen, therefore, that by virtue of the alternate positions ofthe spool 177 as well as the alternate positions of the body 154, anyone of the four vertical passages 173-176 can be employed as the firstmanifold to the indicator device 150 irrespective of the arrangements ofthe other devices 151-153. Thus, with only the four indicator devices150-153 in a given stack, each device can be arranged for individualactuation. Similarly, with more than four indicator devices, as at 150,in a given stack, those units sharing a common first manifold (as at 47in FIG. 1A) will be arranged identically to one another. The remainingunits will, of course, be arranged as required to be coupled to theproper first manifold.

Accordingly, it will be appreciated that the new and improved pneumaticannunciator systems of the present invention are uniquely arranged forreliably providing indications of the occurrence of a malfunction of anindustrial machine. Moreover by virtue of the cooperative relations ofthe several signal-producing controls of these annunciator systems, onlythose indicator relays individually associated with a transducer thatactually senses an undesirable operating condition will be tripped so asto accurately designate the source of the malfunction causing theshutdown of the machine being monitored by the new and improvedannunciator system. In this manner, false indications will not bepresented and there will be no unwarranted resetting of an indicatorrelay as has been typical heretofore with annunciator systems of theprior art.

Furthermore, by virtue of the unique arrangement of the indicator unitsof the present invention, a number of these units can be convenientlystacked into a compact group and various connections made thereto. Asdescribed, the orientation of each unit with respect to the other unitsin the stack will provide one set of alternate connection combinations.Moreover, depending upon the position of the selector valve in eachunit, another set of alternate connection combinations is provided.

While particular embodiments of the present invention have been shownand described, it is apparent that changes and modifications may be madewithout departing from this invention in its broader aspects; and,therefore, the aim in the appended claims is to cover all such changesand modifications as fall within the true spirit and scope of thisinvention.

What is claimed is:

1. A pneumatic annunciator system adapted for monitoring a plurality ofselected conditions respectively subject to change between at least twopredetermined states and comprising: first and second pneumaticindicator means adapted for providing indications representative offirst and second ones of such selected conditions and respectivelyincluding a member operable in response to a pulsed pneumatic signal tosignify the occurrence of a selected one of such states; control meansadapted for selectively enabling said indicator means for independentoperation to their respective signifying condition and including firstand second condition-responsive means respectively coupled to said firstand second indicator means and independently operable in response to theoccurrence of such selected states; and pneumatic signaling meanscoupled to said control means and said first and second indicator meansand operatively arranged and adapted for producing a pulsed pneumaticsignal in response to the operation of either of said first and secondcondition-responsive means for changing to its said signifying positiononly the one of said indicator means associated with the operated one ofsaid condition-responsive means.

2. The pneumatic annunciator system of claim 1 further including firstand second visual indicators operatively associated with said first andsecond members and adapted for respectively providing visual signalsindicative of the movements of said movable members to their respectivesignifying positions.

3. The pneumatic annunciator system of claim 1 wherein such selectedconditions are related to the operation of at least one machine and saidcontrol means further include: means operatively arranged and adaptedfor regulating the operation of such a machine in accordance with thestates of such selected conditions; and means adapted for operating saidregulating means in response to the operation of either of said firstand second condition-responsive means to change the operation ofsuch amachine accordingly.

4. The pneumatic annunciator system of claim 3 further including firstand second visual indicators operatively associated with said first andsecond members which are movable and adapted for respectively providingvisual signals indicative of the movements of said movable members totheir respective signifying positions.

5. The pneumatic annunciator system of claim 1 wherein said controlmeans further include: second pneumatic signaling means coupled to saidfirst and second indicator means and operatively arranged and adaptedfor producing second pneumatic signals for independently restrainingsaid members from their signifying positions before the operation ofsaid first and second condition-responsive means, operation of saidfirst and second condition-responsive means being operative forindependently reducing said second pneumatic signal only on theirrespectively associated indicator means before production of said pulsedpneumatic signal.

6. The pneumatic annunciator system of claim 5 wherein said selectedconditions are related to the operation of at least one machine and saidcontrol means further include: means operatively arranged and adaptedfor regulating the operation of such a machine in accordance with thestates of such selected conditions; and means adapted for operating saidregulating means in response to the operation of either of said firstand second condition-responsive means to change the operation of such amachine accordingly.

7. The pneumatic annunciator system of claim 6 further including firstand second visual indicators operatively associated with said first andsecond members and adapted for respectively providing visual signalsindicative of the movements of said movable members to their respectivesignifying positions.

8. A pneumatic annunciator system adapted for monitoring a plurality ofselected conditions related to the operation of at least one machine andrespectively subject to change between desirable and undesirable states,and comprising: first and second pneumatic indicator means adapted forproviding indications representative of the state of first and secondones of such selected conditions and respectively including a memberoperable in response to pneumatic signals between one conditionsignifying a desirable state and another condition signifying anundesirable state; first and second condition-responsive meansrespectively coupled to said first and second indicator means andindependently operable in response to the occurrence of such desirablestates for enabling said members for operation to their said onecondition and independently operable in response to the occurrence ofsuch undesirable states for enabling said members for operation to theirsaid other conditions; first control means including first pneumaticsignaling means coupled to said first and second indicator means andoperatively arranged and adapted for producing a first pneumatic signalfor operating said first and second members to their said one conditiononly upon such first and second conditions achieving their respectivedesirable states; and second control means including second pneumaticsignaling means coupled to said first control means to said first andsecond indicator means and operatively arranged and adapted forproducing, in response to either of said first and secondcondition-responsive means responding to an undesirable state, a pulsedsecond pneumatic signal for operating to its said other condition onlythe one of said members associated with the responding one of saidcondition-responsive means.

9. The pneumatic annunciator system of claim 8 wherein said firstpneumatic signaling means are operative for producing said firstpneumatic signal for only a predetermined time interval; and furtherincluding third control means coupled to said first and second controlmeans and operative for actuating said second pneumatic signaling meansupon the termination of said first pneumatic signal whenever either ofsaid first and second members are not in their respective one positionat the end of said predetermined time interval.

10. The pneumatic annunciator system of claim 9 further including: meansoperatively arranged and adapted for regulating the operation of such amachine in accordance with the states of such selected conditions; andmeans operatively coupled to said regulating means and said thirdcontrol means and adapted for discontinuing operation of such a machineupon operation of said third control means.

11. The pneumatic annunciator system of claim 10 further including:first and second visual indicators operatively associated with saidfirst and second movable members and adapted for respectively providingvisual signals indicative of the movements of said movable members totheir respective signifying positions.

12. The pneumatic annunciator system of claim 9 wherein the first ofsuch selected conditions is normally in its desirable state so that saidfirst condition-responsive means are normally enabling said firstmovable member for movement to its said one position upon thecommencement of said first pneumatic signal and the second of suchselected conditions is normally in its undesirable state so that saidsecond conditionresponsive means are normally enabling said secondmovable member for movement to its said other position upon thecommencement of said first pneumatic signal.

13. The pneumatic annunciator system of claim 8 wherein such selectedconditions are normally in their respective desirable states so thatsaid first and second condition-responsive means are normally enablingsaid movable members for movement to their said one positions upon thecommencement of said first pneumatic signal and said first pneumaticsignaling means are operative for producing said first pneumatic signalfor only a predetermined time interval; and further including thirdcontrol means coupled to said first and second control means andoperative for actuating said second pneumatic signaling means upon thetermination of said first pneumatic signal whenever either of said firstand second movable members are not in their respective one position atthe end of said predetermined time interval.

14. The pneumatic annunciator system of claim 8 wherein such selectedconditions are normally in their respective undesirable states so thatsaid first and second condition-responsive means are normally enablingsaid movable members for movement to their said other positions uponcommencement of said first pneumatic signal and said first pneumaticsignaling means are operative for producing said first pneumatic signalsfor only a predetermined time interval related to the time anticipatedfor such first and second conditions to reach their respective desiredstates; and further including third control means coupled to said firstand second control means and operative for actuating said secondpneumatic signaling means upon the termination of said first pneumaticsignal whenever either of said first and second movable members have notmoved to their respective one position by the end of said predeterminedtime interval.

15. The pneumatic indicator system of claim 8 wherein such selectedconditions are normally in their respective undesirable states so thatsaid first and second condition-responsive means are normally enablingsaid movable members for movement to their said other positions uponcommencement of said first pneumatic signal and said first pneumaticsignaling means are operative for producing said first pneumatic signalsfor only a predetermined time interval related to the time anticipatedfor such first and second conditions to reach their respective desiredstates; and further including third control means coupled to said firstand second control means and operative in response to said firstpneumatic signal for moving said movable members to their said onepositions whenever said first and second condition-responsive meansfirst operate in response to the occurrence of such desirable states.

16. A pneumatic annunciator system adapted for monitoring a plurality ofselected conditions related to the operation of at least one machine andrespectively subject to change between desirable and undesirable states,and comprising: a plurality of pneumatic indicator means adapted forproviding individual indications representative of the state of suchselected conditions and respectively including a member movable inresponse to pneumatic signals between one position signifying adesirable state and another position signifying an undesirable state; aplurality of condition-responsive means respectively coupled to each ofsaid indicator means and independently operable in response to theoccurrence of such desirable states for enabling said movable membersfor movement to their said one positions and independently operable inresponse to the occurrence of such undesirable states for enabling saidmovable members for movement to their said other positions; firstcontrol means including first pneumatic signaling means coupled to saidindicator means and operatively arranged and adapted for producing afirst pneumatic signal for moving said movable members to their said onepositions only upon such first and second conditions achieving theirrespective desirable states; and second control means including secondpneumatic signaling means coupled to said first control means to saidfirst and second indicator means and operatively arranged and adaptedfor producing pulsed pneumatic signals, means operable in response tocommencement of said first pneumatic signal for actuating said secondpneumatic signaling means to produce a first pulsed pneumatic signal fortemporarily moving said movable members to their respective said otherpositions, and means operable in response to any of saidcondition-responsive means responding to an undesirable state for movingto its said other position only those of said movable members associatedwith the responding conditionresponsive means.

17. The pneumatic annunciator system of claim 16 wherein said means formoving said movable members to their said other positions include meansoperable in response to any of said condition-responsive meansresponding to an undesirable state for actuating said second pneumaticsignaling means to produce a second pulsed pneumatic signal for movingto its said other position only those of said movable members associatedwith the responding condition-responsive means, and means operativelyassociated with said indicator means for retaining said first pneumaticsignal to prevent movement of the others of said movable members frommoving to their said other positions in response to said second pulsedpneumatic signal.

18. The pneumatic annunciator system of claim 17 further including: aplurality of visual indicators respectively associated with each of saidmovable members and adapted for respectively providing visual signalsindicative of the positions of said movable members.

19. The pneumatic annunciator system of claim 17 further including:means operatively arranged and adapted for regulating the operation ofsuch a machine in accordance with the states of such selectedconditions; and means operatively coupled to said regulating means andsaid second control means and adapted for discontinuing operation ofsuch a machine upon operation of said second pneumatic signaling meansto produce said second pulsed pneumatic signal.

20. The pneumatic annunciator system of claim 19 further including: aplurality of visual indicators respectively as sociated with each ofsaid movable members and adapted for respectively providing visualsignals indicative of the positions of said movable members.

21. The pneumatic annunciator system of claim 17 wherein at least one ofsaid condition-responsive means is adapted for monitoring a conditionnormally in a desired state upon starting of such a machine so that saidone condition-responsive means will normally enable the movable memberassociated therewith for movement to its said one position uponcommencement ofsaid first pneumatic signal.

22. The pneumatic annunciator system of claim 17 wherein at least one ofsaid condition-responsive means is adapted for monitoring a conditionnormally in an undesirable state upon starting of such a machine butwhich condition reaches a desirable state within a known time intervalafter starting of such a machine and said first pneumatic signalingmeans are operative for producing said first pneumatic signal for only apredetermined time interval somewhat greater than said known timeinterval so that said one condition-responsive means must enable themovable member associated therewith for movement to its said oneposition before the termination of said first pneumatic signal.

23. The pneumatic annunciator system of claim 22 wherein at leastanother one of said condition-responsive means is adapted for monitoringa condition normally in a desired state upon starting of such a machineso that said other conditionresponsive means will normally enable themovable member associated therewith for movement to its said oneposition upon commencement of said first pneumatic signal.

24. The pneumatic annunciator system of claim 17 wherein at least one ofsaid condition-responsive means is adapted for monitoring a conditionnormally in an undesirable state upon starting of such a machine butwhich condition reaches a desirable state within an undetermined timeinterval after starting of such a machine; and further including thirdcontrol means coupled to said first and second control means andoperative in response to said first pneumatic signal for moving themovable member associated with said one conditionresponsive means to itssaid one position whenever said one condition-responsive means firstoperates in response to the occurrence of a desirable state in thecondition monitored thereby.

25. The pneumatic annunciator system of claim 24 wherein at leastanother one of said condition-responsive means is adapted for monitoringa condition normally in a desired state upon starting of such a machineso that said other conditionresponsive means will normally enable themovable member associated therewith for movement to its said oneposition upon commencement of said first pneumatic signal.

26. The pneumatic annunciator system of claim 24 wherein at leastanother one of said condition-responsive means is adapted for monitoringa condition normally in an undesirable state upon starting of such amachine but which condition reaches a desirable state within a knowntime interval after starting of such a machine and said first pneumaticsignaling means are operative for producing said first pneumatic signalfor only a predetermined time interval somewhat greater than said knowntime interval so that said other condition-responsive means must enablethe movable member associated therewith for movement to its said oneposition before the termination of said first pneumatic signal.

27. The pneumatic annunciator system of claim 26 wherein at least athird one of said condition-responsive means is adapted for monitoring acondition normally in a desired state upon starting of such a machine sothat said third conditionresponsive means will normally enable themovable member associated therewith for movement to its said oneposition upon commencement of said first pneumatic signal.

28. A pneumatic annunciator system adapted for controlling the operationof at least one machine and monitoring a plurality of selectedconditions related to its operation and which are subject to changebetween desirable and undesirable states, comprising a plurality ofpneumatic indicator means adapted for providing individual indicationsrepresentative of the state of such selected conditions and including apressure-responsive member movable within an enclosed chamber betweenfirst and second positions which signify. as assigned, a desirable stateand an undesirable state; control means connected to such one machinefor controlling its continued operation, and for further terminating itsoperation. such machine being characterized in that a predeterminedinterval of time is required for said control means to terminateoperation of such machine; a plurality of condition-responsive valveseach adapted to be independently closed in response to the occurrence ofa desirable state in its monitored condition and to be independentlyopened in response to the occurrence of an undesirable state in itsmonitored condition for venting to form a pneumatic signal indicative ofthe change thereof; connective means communicating saidcondition-responsive valves respectively to said pneumatic indicatormeans in a manner such that said pneumatic indicator means is enabledfor subsequent operation; pneumatic pulse generator means for forming apulsed pneumatic signal respectively applied to said pneumatic indicatormeans for moving said pressureresponsive members to either said first orsecond positions; each of said pneumatic indicator means being soconstructed and arranged that its pressure-responsive member is enabledto be moved to a position indicative of an undesirable state only afteroperation of said respective condition-responsive valve associatedtherewith to form a pneumatic signal indicative of the change thereof;and said control means being at least partially dependent for initiationof its operation on operation of said condition-responsive valves forterminating operation of such machine.

29. The annunciator system of claim 28 wherein such machine isterminated in its operation over a predetermined interval of time, andsaid pulse generator means forms a pulsed pneumatic signal for saidpneumatic indicator means, which signal is formed and completed prior tothe end of the predetermined interval of time.

30. The annunciator system of claim 28 including a common manifoldsystem connected to at least a pair of said pneumatic indicator means,and also in communication with said connective means, for communicatinga pneumatic signal from said condition-responsive valve respectivelyassociated with said pneumatic indicator means; and check valve meansoperatively incorporated in said connective means for communicating apressure change from said condition-responsive valve to said respectivepneumatic indicator means associated therewith for enabling itsoperation, said check valve means further preventing the communicationof the pressure change through said common manifold system to theremaining one of said pair of pneumatic indicator means.

31. The annunciator system of claim 28 including a common manifoldpassage means connected between at least a pair of said pneumaticindicator means for applying a pressure level on saidpressure-responsive members for maintaining said pressure-responsivemembers in positions indicative of their respective desirable states andtending to oppose the pneumatic signal applied thereto by said pulsegenerator means; check valve means isolating said pneumatic indicatormeans from pressure drops communicated through said common manifoldpassage means; and wherein said pressureresponsive member is moved to aposition indicating an undesirable state of such machine as sensed bysaid conditionresponsive valves.

32. The annunciator system of claim 28 further including a manifoldpassage means connected to one of said pneumatic indicator means forapplying a pressure level to said pressureresponsive member in saidenclosed chamber tending to maintain said member in a positionindicating a desirable state; said manifold passage means supplying itspressure level through a check valve means which is so connected as tomaintain the pressure level acting on said pressure-responsive memberfrom said manifold passage means; said connective means communicatingsaid condition-responsive valve to said pressure-responsive member forventing the pressure level acting on said pressure-responsive memberthrough said conditionresponsive valve, and said check valve meansventing said manifold passage means through said condition-responsivevalve; an additional passage means communicated with said enclosedchamber for supplying the pulsed pneumatic signal from said pulsegenerator means, said additional passage means connected with saidenclosed chamber such that said pulsed pneumatic signal tends to movesaid pressure-responsive member to the position indicative of anundesirable state, and said movement is accomplished when saidconditionresponsive valve has opened to vent and said movement is notaccomplished when said condition-responsive valve has not opened tovent.

33. The annunciator system of claim 28 further including a manifoldpassage means connected to one of said pneumatic indicator means forapplying a pressure level to said pressureresponsive member in saidenclosed chamber tending to maintain said member in a positionindicating a desirable state; said manifold passage means supplying itspressure level through a check valve means which is so connected as tomaintain the pressure level acting on said pressure-responsive memberfrom said manifold passage means; said control means being operativelyconnected to and controlled by the pressure level in said manifoldpassage means such that a drop in pressure created by the opening tovent of a selected condition-responsive valve coupled through a checkvalve means lowers the pressure in said manifold passage means andinitiates termination of operation of such machine; and wherein suchmachine, during its termination of operation, changes the selectedconditions monitored by said condition-responsive valves which changesattain an undesirable state monitored by their respectivecondition-responsive valves; said pulse generator means forming a pulsedpneumatic signal respectively applied to said pneumatic indicator meansafter the opening to vent of one selected condition-responsive valve butbefore the opening to vent of the remainder of said condition-responsivevalves as such machine terminates operation and the selected conditionsmonitored by the remainder of said condition-responsive valves attainthe undesired state.

34. The annunciator system of claim 28 further including a plurality ofvisual indicators respectively associated with each of saidpressure-responsive members and is adapted for providing visual signalsindicative of the positions of said pressure-responsive members.

35. The annunciator system of claim 28 wherein one or more of saidcondition-responsivc valves is adapted to monitor a condition normallyin an undesirable state upon starting of such a machine but whichcondition reaches a desirable state within a known time interval afterstarting such machine and such condition is monitored by one of saidcondition-responsive valves; and further including a manifold passagemeans connected to at least one of said pneumatic indicator means forderiving a pressure level from said means indicative of the open orclosed condition-responsive valve associated therewith; said manifoldpassage means being operatively connected to said control means forterminating operation of such machine on o enin of one of saidcondition-responsive valves as derived t roug said pneumatlc indicatormeans; and

enabling means interposed between said control means and said manifoldpassage means for enabling operation of said control means until afterpassage of the known time interval.

36. The annunciator system of claim 35 wherein the known time intervalis determined by an event related to the operation of such machine.

37. The annunciator system of claim 35 further including a plurality ofvisual indicators respectively associated with each of saidpressure-responsive members and is adapted for providing visual signalsindicative of the positions of said pressure-responsive members.

38. The annunciator system of claim 35 wherein said enabling meansincludes a pressure source which supplies pneumatic pressure to saidmanifold passage means at a controlled rate, and so long as said onecondition remains in an undesirable state said condition-responsivevalve associated therewith opens to vent said manifold passage means;and further including means associated with said control meansresponsive to an increase in pressure in said manifold passage meanswhich enables said control means to be responsive to a subsequent dropin pressure in said manifold passage means in terminating operation ofsuch machine.

39. The annunciator system of claim 38 wherein said check valveassociated with said condition-responsive valve which is closed afterpassage of a known time interval vents said manifold passage meansthrough said condition-responsive valve continuously until saidcondition-responsive valve is closed.

1. A pneumatic annunciator system adapted for monitoring a plurality ofselected conditions respectively subject to change between at least twopredetermined states and comprising: first and second pneumaticindicator means adapted for providing indications representative offirst and second ones of such selected conditions and respectivelyincluding a member operable in response to a pulsed pneumatic signal tosignify the occurrence of a selected one of such states; control meansadapted for selectively enabling said indicator means for independentoperation to their respective signifying condition and including firstand second condition-responsive means respectively coupled to said firstand second indicator means and independently operable in response to theoccurrence of such selected states; and pneumatic signaling meanscoupled to said control means and said first and second indicator meansand operatively arranged and adapted for producing a pulsed pneumaticsignal in response to the operation of either of said first and secondcondition-responsive means for changing to its said signifying positiononly the one of said indicator means associated with the operated one ofsaid condition-responsive means.
 2. The pneumatic annunciator system ofclaim 1 further including first and second visual indicators operativelyassociated with said first and second members and adapted forrespectively providing visuAl signals indicative of the movements ofsaid movable members to their respective signifying positions.
 3. Thepneumatic annunciator system of claim 1 wherein such selected conditionsare related to the operation of at least one machine and said controlmeans further include: means operatively arranged and adapted forregulating the operation of such a machine in accordance with the statesof such selected conditions; and means adapted for operating saidregulating means in response to the operation of either of said firstand second condition-responsive means to change the operation of such amachine accordingly.
 4. The pneumatic annunciator system of claim 3further including first and second visual indicators operativelyassociated with said first and second members which are movable andadapted for respectively providing visual signals indicative of themovements of said movable members to their respective signifyingpositions.
 5. The pneumatic annunciator system of claim 1 wherein saidcontrol means further include: second pneumatic signaling means coupledto said first and second indicator means and operatively arranged andadapted for producing second pneumatic signals for independentlyrestraining said members from their signifying positions before theoperation of said first and second condition-responsive means, operationof said first and second condition-responsive means being operative forindependently reducing said second pneumatic signal only on theirrespectively associated indicator means before production of said pulsedpneumatic signal.
 6. The pneumatic annunciator system of claim 5 whereinsaid selected conditions are related to the operation of at least onemachine and said control means further include: means operativelyarranged and adapted for regulating the operation of such a machine inaccordance with the states of such selected conditions; and meansadapted for operating said regulating means in response to the operationof either of said first and second condition-responsive means to changethe operation of such a machine accordingly.
 7. The pneumaticannunciator system of claim 6 further including first and second visualindicators operatively associated with said first and second members andadapted for respectively providing visual signals indicative of themovements of said movable members to their respective signifyingpositions.
 8. A pneumatic annunciator system adapted for monitoring aplurality of selected conditions related to the operation of at leastone machine and respectively subject to change between desirable andundesirable states, and comprising: first and second pneumatic indicatormeans adapted for providing indications representative of the state offirst and second ones of such selected conditions and respectivelyincluding a member operable in response to pneumatic signals between onecondition signifying a desirable state and another condition signifyingan undesirable state; first and second condition-responsive meansrespectively coupled to said first and second indicator means andindependently operable in response to the occurrence of such desirablestates for enabling said members for operation to their said onecondition and independently operable in response to the occurrence ofsuch undesirable states for enabling said members for operation to theirsaid other conditions; first control means including first pneumaticsignaling means coupled to said first and second indicator means andoperatively arranged and adapted for producing a first pneumatic signalfor operating said first and second members to their said one conditiononly upon such first and second conditions achieving their respectivedesirable states; and second control means including second pneumaticsignaling means coupled to said first control means to said first andsecond indicator means and operatively arranged and adapted forproducing, in response to either of said first and secondcondition-responsive means responding to an Undesirable state, a pulsedsecond pneumatic signal for operating to its said other condition onlythe one of said members associated with the responding one of saidcondition-responsive means.
 9. The pneumatic annunciator system of claim8 wherein said first pneumatic signaling means are operative forproducing said first pneumatic signal for only a predetermined timeinterval; and further including third control means coupled to saidfirst and second control means and operative for actuating said secondpneumatic signaling means upon the termination of said first pneumaticsignal whenever either of said first and second members are not in theirrespective one position at the end of said predetermined time interval.10. The pneumatic annunciator system of claim 9 further including: meansoperatively arranged and adapted for regulating the operation of such amachine in accordance with the states of such selected conditions; andmeans operatively coupled to said regulating means and said thirdcontrol means and adapted for discontinuing operation of such a machineupon operation of said third control means.
 11. The pneumaticannunciator system of claim 10 further including: first and secondvisual indicators operatively associated with said first and secondmovable members and adapted for respectively providing visual signalsindicative of the movements of said movable members to their respectivesignifying positions.
 12. The pneumatic annunciator system of claim 9wherein the first of such selected conditions is normally in itsdesirable state so that said first condition-responsive means arenormally enabling said first movable member for movement to its said oneposition upon the commencement of said first pneumatic signal and thesecond of such selected conditions is normally in its undesirable stateso that said second condition-responsive means are normally enablingsaid second movable member for movement to its said other position uponthe commencement of said first pneumatic signal.
 13. The pneumaticannunciator system of claim 8 wherein such selected conditions arenormally in their respective desirable states so that said first andsecond condition-responsive means are normally enabling said movablemembers for movement to their said one positions upon the commencementof said first pneumatic signal and said first pneumatic signaling meansare operative for producing said first pneumatic signal for only apredetermined time interval; and further including third control meanscoupled to said first and second control means and operative foractuating said second pneumatic signaling means upon the termination ofsaid first pneumatic signal whenever either of said first and secondmovable members are not in their respective one position at the end ofsaid predetermined time interval.
 14. The pneumatic annunciator systemof claim 8 wherein such selected conditions are normally in theirrespective undesirable states so that said first and secondcondition-responsive means are normally enabling said movable membersfor movement to their said other positions upon commencement of saidfirst pneumatic signal and said first pneumatic signaling means areoperative for producing said first pneumatic signals for only apredetermined time interval related to the time anticipated for suchfirst and second conditions to reach their respective desired states;and further including third control means coupled to said first andsecond control means and operative for actuating said second pneumaticsignaling means upon the termination of said first pneumatic signalwhenever either of said first and second movable members have not movedto their respective one position by the end of said predetermined timeinterval.
 15. The pneumatic indicator system of claim 8 wherein suchselected conditions are normally in their respective undesirable statesso that said first and second condition-responsive means are normallyenabling said movable members for movemEnt to their said other positionsupon commencement of said first pneumatic signal and said firstpneumatic signaling means are operative for producing said firstpneumatic signals for only a predetermined time interval related to thetime anticipated for such first and second conditions to reach theirrespective desired states; and further including third control meanscoupled to said first and second control means and operative in responseto said first pneumatic signal for moving said movable members to theirsaid one positions whenever said first and second condition-responsivemeans first operate in response to the occurrence of such desirablestates.
 16. A pneumatic annunciator system adapted for monitoring aplurality of selected conditions related to the operation of at leastone machine and respectively subject to change between desirable andundesirable states, and comprising: a plurality of pneumatic indicatormeans adapted for providing individual indications representative of thestate of such selected conditions and respectively including a membermovable in response to pneumatic signals between one position signifyinga desirable state and another position signifying an undesirable state;a plurality of condition-responsive means respectively coupled to eachof said indicator means and independently operable in response to theoccurrence of such desirable states for enabling said movable membersfor movement to their said one positions and independently operable inresponse to the occurrence of such undesirable states for enabling saidmovable members for movement to their said other positions; firstcontrol means including first pneumatic signaling means coupled to saidindicator means and operatively arranged and adapted for producing afirst pneumatic signal for moving said movable members to their said onepositions only upon such first and second conditions achieving theirrespective desirable states; and second control means including secondpneumatic signaling means coupled to said first control means to saidfirst and second indicator means and operatively arranged and adaptedfor producing pulsed pneumatic signals, means operable in response tocommencement of said first pneumatic signal for actuating said secondpneumatic signaling means to produce a first pulsed pneumatic signal fortemporarily moving said movable members to their respective said otherpositions, and means operable in response to any of saidcondition-responsive means responding to an undesirable state for movingto its said other position only those of said movable members associatedwith the responding condition-responsive means.
 17. The pneumaticannunciator system of claim 16 wherein said means for moving saidmovable members to their said other positions include means operable inresponse to any of said condition-responsive means responding to anundesirable state for actuating said second pneumatic signaling means toproduce a second pulsed pneumatic signal for moving to its said otherposition only those of said movable members associated with theresponding condition-responsive means, and means operatively associatedwith said indicator means for retaining said first pneumatic signal toprevent movement of the others of said movable members from moving totheir said other positions in response to said second pulsed pneumaticsignal.
 18. The pneumatic annunciator system of claim 17 furtherincluding: a plurality of visual indicators respectively associated witheach of said movable members and adapted for respectively providingvisual signals indicative of the positions of said movable members. 19.The pneumatic annunciator system of claim 17 further including: meansoperatively arranged and adapted for regulating the operation of such amachine in accordance with the states of such selected conditions; andmeans operatively coupled to said regulating means and said secondcontrol means and adapted for discontinuing operation of such a machineupon operation of saId second pneumatic signaling means to produce saidsecond pulsed pneumatic signal.
 20. The pneumatic annunciator system ofclaim 19 further including: a plurality of visual indicatorsrespectively associated with each of said movable members and adaptedfor respectively providing visual signals indicative of the positions ofsaid movable members.
 21. The pneumatic annunciator system of claim 17wherein at least one of said condition-responsive means is adapted formonitoring a condition normally in a desired state upon starting of sucha machine so that said one condition-responsive means will normallyenable the movable member associated therewith for movement to its saidone position upon commencement of said first pneumatic signal.
 22. Thepneumatic annunciator system of claim 17 wherein at least one of saidcondition-responsive means is adapted for monitoring a conditionnormally in an undesirable state upon starting of such a machine butwhich condition reaches a desirable state within a known time intervalafter starting of such a machine and said first pneumatic signalingmeans are operative for producing said first pneumatic signal for only apredetermined time interval somewhat greater than said known timeinterval so that said one condition-responsive means must enable themovable member associated therewith for movement to its said oneposition before the termination of said first pneumatic signal.
 23. Thepneumatic annunciator system of claim 22 wherein at least another one ofsaid condition-responsive means is adapted for monitoring a conditionnormally in a desired state upon starting of such a machine so that saidother condition-responsive means will normally enable the movable memberassociated therewith for movement to its said one position uponcommencement of said first pneumatic signal.
 24. The pneumaticannunciator system of claim 17 wherein at least one of saidcondition-responsive means is adapted for monitoring a conditionnormally in an undesirable state upon starting of such a machine butwhich condition reaches a desirable state within an undetermined timeinterval after starting of such a machine; and further including thirdcontrol means coupled to said first and second control means andoperative in response to said first pneumatic signal for moving themovable member associated with said one condition-responsive means toits said one position whenever said one condition-responsive means firstoperates in response to the occurrence of a desirable state in thecondition monitored thereby.
 25. The pneumatic annunciator system ofclaim 24 wherein at least another one of said condition-responsive meansis adapted for monitoring a condition normally in a desired state uponstarting of such a machine so that said other condition-responsive meanswill normally enable the movable member associated therewith formovement to its said one position upon commencement of said firstpneumatic signal.
 26. The pneumatic annunciator system of claim 24wherein at least another one of said condition-responsive means isadapted for monitoring a condition normally in an undesirable state uponstarting of such a machine but which condition reaches a desirable statewithin a known time interval after starting of such a machine and saidfirst pneumatic signaling means are operative for producing said firstpneumatic signal for only a predetermined time interval somewhat greaterthan said known time interval so that said other condition-responsivemeans must enable the movable member associated therewith for movementto its said one position before the termination of said first pneumaticsignal.
 27. The pneumatic annunciator system of claim 26 wherein atleast a third one of said condition-responsive means is adapted formonitoring a condition normally in a desired state upon starting of sucha machine so that said third condition-responsive means will normallyenable the movable member associated therewith for movement to its saidone position Upon commencement of said first pneumatic signal.
 28. Apneumatic annunciator system adapted for controlling the operation of atleast one machine and monitoring a plurality of selected conditionsrelated to its operation and which are subject to change betweendesirable and undesirable states, comprising a plurality of pneumaticindicator means adapted for providing individual indicationsrepresentative of the state of such selected conditions and including apressure-responsive member movable within an enclosed chamber betweenfirst and second positions which signify, as assigned, a desirable stateand an undesirable state; control means connected to such one machinefor controlling its continued operation, and for further terminating itsoperation, such machine being characterized in that a predeterminedinterval of time is required for said control means to terminateoperation of such machine; a plurality of condition-responsive valveseach adapted to be independently closed in response to the occurrence ofa desirable state in its monitored condition and to be independentlyopened in response to the occurrence of an undesirable state in itsmonitored condition for venting to form a pneumatic signal indicative ofthe change thereof; connective means communicating saidcondition-responsive valves respectively to said pneumatic indicatormeans in a manner such that said pneumatic indicator means is enabledfor subsequent operation; pneumatic pulse generator means for forming apulsed pneumatic signal respectively applied to said pneumatic indicatormeans for moving said pressure-responsive members to either said firstor second positions; each of said pneumatic indicator means being soconstructed and arranged that its pressure-responsive member is enabledto be moved to a position indicative of an undesirable state only afteroperation of said respective condition-responsive valve associatedtherewith to form a pneumatic signal indicative of the change thereof;and said control means being at least partially dependent for initiationof its operation on operation of said condition-responsive valves forterminating operation of such machine.
 29. The annunciator system ofclaim 28 wherein such machine is terminated in its operation over apredetermined interval of time, and said pulse generator means forms apulsed pneumatic signal for said pneumatic indicator means, which signalis formed and completed prior to the end of the predetermined intervalof time.
 30. The annunciator system of claim 28 including a commonmanifold system connected to at least a pair of said pneumatic indicatormeans, and also in communication with said connective means, forcommunicating a pneumatic signal from said condition-responsive valverespectively associated with said pneumatic indicator means; and checkvalve means operatively incorporated in said connective means forcommunicating a pressure change from said condition-responsive valve tosaid respective pneumatic indicator means associated therewith forenabling its operation, said check valve means further preventing thecommunication of the pressure change through said common manifold systemto the remaining one of said pair of pneumatic indicator means.
 31. Theannunciator system of claim 28 including a common manifold passage meansconnected between at least a pair of said pneumatic indicator means forapplying a pressure level on said pressure-responsive members formaintaining said pressure-responsive members in positions indicative oftheir respective desirable states and tending to oppose the pneumaticsignal applied thereto by said pulse generator means; check valve meansisolating said pneumatic indicator means from pressure dropscommunicated through said common manifold passage means; and whereinsaid pressure-responsive member is moved to a position indicating anundesirable state of such machine as sensed by said condition-responsivevalves.
 32. The annunciator system of claim 28 further including amanIfold passage means connected to one of said pneumatic indicatormeans for applying a pressure level to said pressure-responsive memberin said enclosed chamber tending to maintain said member in a positionindicating a desirable state; said manifold passage means supplying itspressure level through a check valve means which is so connected as tomaintain the pressure level acting on said pressure-responsive memberfrom said manifold passage means; said connective means communicatingsaid condition-responsive valve to said pressure-responsive member forventing the pressure level acting on said pressure-responsive memberthrough said condition-responsive valve, and said check valve meansventing said manifold passage means through said condition-responsivevalve; an additional passage means communicated with said enclosedchamber for supplying the pulsed pneumatic signal from said pulsegenerator means, said additional passage means connected with saidenclosed chamber such that said pulsed pneumatic signal tends to movesaid pressure-responsive member to the position indicative of anundesirable state, and said movement is accomplished when saidcondition-responsive valve has opened to vent and said movement is notaccomplished when said condition-responsive valve has not opened tovent.
 33. The annunciator system of claim 28 further including amanifold passage means connected to one of said pneumatic indicatormeans for applying a pressure level to said pressure-responsive memberin said enclosed chamber tending to maintain said member in a positionindicating a desirable state; said manifold passage means supplying itspressure level through a check valve means which is so connected as tomaintain the pressure level acting on said pressure-responsive memberfrom said manifold passage means; said control means being operativelyconnected to and controlled by the pressure level in said manifoldpassage means such that a drop in pressure created by the opening tovent of a selected condition-responsive valve coupled through a checkvalve means lowers the pressure in said manifold passage means andinitiates termination of operation of such machine; and wherein suchmachine, during its termination of operation, changes the selectedconditions monitored by said condition-responsive valves which changesattain an undesirable state monitored by their respectivecondition-responsive valves; said pulse generator means forming a pulsedpneumatic signal respectively applied to said pneumatic indicator meansafter the opening to vent of one selected condition-responsive valve butbefore the opening to vent of the remainder of said condition-responsivevalves as such machine terminates operation and the selected conditionsmonitored by the remainder of said condition-responsive valves attainthe undesired state.
 34. The annunciator system of claim 28 furtherincluding a plurality of visual indicators respectively associated witheach of said pressure-responsive members and is adapted for providingvisual signals indicative of the positions of said pressure-responsivemembers.
 35. The annunciator system of claim 28 wherein one or more ofsaid condition-responsive valves is adapted to monitor a conditionnormally in an undesirable state upon starting of such a machine butwhich condition reaches a desirable state within a known time intervalafter starting such machine and such condition is monitored by one ofsaid condition-responsive valves; and further including a manifoldpassage means connected to at least one of said pneumatic indicatormeans for deriving a pressure level from said means indicative of theopen or closed condition-responsive valve associated therewith; saidmanifold passage means being operatively connected to said control meansfor terminating operation of such machine on opening of one of saidcondition-responsive valves as derived through said pneumatic indicatormeans; and enabling means interposed between said control means and saidmanifold passage means for enabling operation of said control meansuntil after passage of the known time interval.
 36. The annunciatorsystem of claim 35 wherein the known time interval is determined by anevent related to the operation of such machine.
 37. The annunciatorsystem of claim 35 further including a plurality of visual indicatorsrespectively associated with each of said pressure-responsive membersand is adapted for providing visual signals indicative of the positionsof said pressure-responsive members.
 38. The annunciator system of claim35 wherein said enabling means includes a pressure source which suppliespneumatic pressure to said manifold passage means at a controlled rate,and so long as said one condition remains in an undesirable state saidcondition-responsive valve associated therewith opens to vent saidmanifold passage means; and further including means associated with saidcontrol means responsive to an increase in pressure in said manifoldpassage means which enables said control means to be responsive to asubsequent drop in pressure in said manifold passage means interminating operation of such machine.
 39. The annunciator system ofclaim 38 wherein said check valve associated with saidcondition-responsive valve which is closed after passage of a known timeinterval vents said manifold passage means through saidcondition-responsive valve continuously until said condition-responsivevalve is closed.